1. Field of the Invention
This invention pertains to power supplies for connection to readily available power sources such as 60 Hz, 110 or 220 volts. More specifically, it relates to a switching regulator power supply utilizing DC coupling circuitry from secondary to primary and from primary to secondary, and utilizes a ferrite core transformer.
2. Description of the Prior Art
Power supplies typically utilize laminated cores in transformers used to obtain the working voltage or voltages desired. This is accomplished by directly transforming the 60 Hz input voltage. Power supplies utilizing such transformers can be designed to operate quite satisfactorily, but have the disadvantage of large bulk and weight which cannot readily be tolerated for some applications. Associated circuitry, such as filter capacitors, also must be large. To reduce size and weight, unregulated secondary inverters have been provided to supply power. These devices are difficult to regulate. Secondary regulators are typically used, causing a reduction in circuit efficiency and a more expensive power supply.
The switching regulator power supply provides high efficiency and low cost. It commonly incorporates a transformer wound on a ferrite core wherein an energy storage period is used to store energy in the transformer primary and an energy transfer period is used to transfer energy from the primary to the secondary of the transformer when the primary circuit is opened. The basic switching regulator power supply monitors electrical parameters in the primary circuit, having an AC coupling only through the transformer to the secondary circuit. Often, a small 60 Hz transformer must be used to assure that the power supply will work upon application of line voltage.
A more advanced switching regulator power supply utilizes a transformer coupled feedback circuit from the secondary circuit to the primary circuit. This permits monitoring secondary power parameters and adjusting the energy storage cycle accordingly, to a degree of accuracy not achievable when the primary circuit only is monitored as in the case of the basic switching regulator power supply.
The switching regulator power supply herein described and claimed utilizes a DC coupling technique from secondary to primary and from primary to secondary in the form of optical coupling devices. Use of optical coupling techniques provide for enormously increased reliability by way of permitting comparatively sophisticated testing during manufacture and before installation. The optical coupling allows isolation of primary and secondary circuits which is not achievable where transformers are used for such coupling. Therefore, when the manufacturing and testing stage is completed in the case of the optically coupled units, the possibility of providing a user with a working power supply is greatly enhanced. Through the use of optical coupling, a light, small, switching regulator power supply is available.